Session-title calls carry a 64-token output cap and rely on the adapter to
keep reasoning out of it. llm-deepseek maps purpose 'session-title' to
thinking disabled, but llm-pi-ai ignored the purpose, so pi-ai routes sent
title calls at the route's default effort. On HFAI's adaptive-thinking
Claude models (profile reasoning: max) the thinking consumed the cap, the
call finished with max-tokens, and the session kept its fallback title.
The pi-ai adapter now dispatches a session-title request at the model's
lowest supported level: off when the model offers it, otherwise the
lowest declared level. GenerateOptions.purpose documents that obligation
for every adapter.